Question: If $6a + b = 1$ and $6x + y + 6z = -9$, what is $4b + 7y + 24a + 42z + 42x$ ?
Answer: $= 24a + 4b + 42x + 7y + 42z$ $= (4) \cdot (6a + b) + (7) \cdot (6x + y + 6z)$ $= (4) \cdot (1) + (7) \cdot (-9)$ $= 4 - 63$ $= -59$